This invention relates to a sensory apparatus of the type as already known from Federal Republic of Germany Patent DE-PS No. 26 53 864. Such sensory apparatus, based upon its response sensitivity and its broadband signal detection and signal transmission, can distinguish the state of the substances passing by the apparatus, particularly substances to be mixed or granulated in the container. The apparatus can distinguish the state of the substances as regards the particle size and frequency as well as the viscosity of the contents of the container, whereby the apparatus indicates not only an average value of the "kinetic energy" exerted on the sensor by the substance passing by the sensor, but also, in a given case, a spectrum of impulse signals according to the occurrence of particles.
The previously-known designs are longitudinally stretched whereby the sensor is positioned on the head of a bending rod and extensometer strips are provided on a bending zone adjacent to a fixed clamping area on the foot side of the sensor for converting the mechanical bending stress into electrical signals. The sensory apparatus is designed like a telescope rod, whereby the sensor, and the foot of the sensor, with the measuring elements positioned thereon, is enclosed by a tube portion which is positioned inside of a further sleeve which is connected on its side to the wall of the container. This construction of the sensory apparatus takes into consideration the practical requirement, which is not stated in the aforementioned patent, that the sensor can be retracted into the sleeve when no measuring results are required. This prevents damaging of the exposed sensor, for instance, when chunky substances are put into the container for mixing. Accordingly, in the practically known sensory apparatus, the sensor is fastened on the cover of the container so that it can be retracted from the area where the substances are to be mixed.
Retracting the sensor, however, results only in a limited mechanical protection and, furthermore, the foot section of the sensor remains exposed to soiling as well as to chemical and thermal reactions. Furthermore, the telescoping feature of the sensor is constructionally expensive and inconvenient during measurements because, on the one hand, in order to provide a protected retracting position, the sensory apparatus has to be positioned in the cover of the container but, on the other hand, a sufficient sliding length has to be provided so that it can reach into the area where the substance is being moved in the container.
Accordingly, an object of the present invention is to create a sensory apparatus which significantly reduces the abovementioned disadvantages and which provides simple and fast measurements at high operational reliability.
The present invention deviates from the generally rodshaped construction of the aforementioned sensor. According to the present invention, the actual sensor head extends from the wall, whereas the deformation area which is provided for measurement detection is in the form of an extended area, preferably a membrane-like foot. The extended area can be arranged flat in the wall of the container. This flat configuration is especially important when the substances in the container are being moved by a throwing movement, for instance, as is the case of a configuration of a mixing implement which is near, or at, the ground, and which generates a funnel movement whereby the walls contribute to forming a funnel. A foot, adapted to the wall, makes possible an interference-free configuration of the funnel.
The reduced measurements and mass of the apparatus improve the response sensitivity of the sensor and the bandwidth of the signal, whereby the compact design simultaneously results in suppressing interfering self-oscillations.
Because of the configuration of the foot which lies flat on the wall and because of the total height of the sensory apparatus extending into the container, which is essentially reduced to the head of the sensor, the sensory apparatus is not much stressed. Also, because of its sturdier design, it can withstand even coarser materials in the container. The sensor no longer needs to be equipped with a retraction position. This allows constructing the sensory apparatus without "moving parts", that is, without telescoping sliding parts, as well as without the corresponding drives and controls. Thus the sensory apparatus is simple and sturdier and is constantly ready for operation.
The greater strength of the sensory apparatus also makes it possible to position it in a deeper lying wall area of the container, rather than in the cover as was previously done. This allows it to reach the substances to be mixed even if the container is only partially filled. Limited measuring conditions which so far had to be taken into consideration, such as requiring a given high degree of fullness of the container for creating sufficient impact of the substances on the sensor, are no longer applicable.
The deformable plate simultaneously forms a separation wall, on the one side between the sensor head and, on the other side, between the measuring receiver which protects the latter mechanically and chemically. Essentially, various mechanical and electrical signal converters can be utilized behind the deformable plate. Preferably, tested extensometer strip elements are used for this purpose. They are bonded to the backside of the deformable plate and signal the deformation of the plate.
The deformable plate can be configured in various shapes, such as, for instance, in band-like laterally extending shapes, for a sensor having from the outset a fixed triggering direction. Preferably, an extended elastic surface membrane is used as a deformable plate whereby the surface extension allows the positioning of distributed measuring receivers, and accordingly, also the analysis of the signals in regard to the triggering direction for the sensor.
Other features which are considered characteristic of the invention are set forth in the appended claims.
Although the invention is illustrated and described in relationship to specific embodiments, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.